1. Field of the Invention
The present invention relates to an electric junction box having a drainage device and suitable for use in vehicle such as automotive vehicle.
2. Description of the Related Art
A vehicle such as automotive vehicle is generally equipped with a variety of electricity activated components, for example, a lamp such as a head lamp and a rear lamp, and a motor such as a starter motor and a motor for driving an air-conditioner. To provide these components with electricity, an electric junction block is distributed within automotive vehicle, as needed. The junction block is constituted by a plurality of electrical circuit units such as a fuse and a relay.
Further, as the junction block is generally contemplated to include a fuse, a relay, and a bus bar, the electric junction box is referred to a fuse block and a relay box. The junction block has been often called “electric junction box” in its broad concept. As used herein, the term “the electric junction box” should be contemplated to include all of the foregoing fuse block, relay box, and junction block.
Exemplary electric junction box is comprised of a wiring board having one or more electric components installed therein; a connector block having a body and a terminal passing through the bottom wall of the body and being electrically connected to the wiring board at its one end portion; a case being disposed above the bottom wall of the body, having a hole for passing the other end portion of the terminal therethrough and being configured to receive both the wiring board and the connector block therewithin.
An electric component such as a fuse can be coupled to the terminal passing through hole. As the fuse can be releasably coupled to the case, maintenance operation thereof can be easily performed. On the other hands, there is high possibility that water can leak into the case via the hole. Further, the water can adversely affect the wiring board received within the case and the electric components mounted on the wiring board. For example, due to the water, short-circuit failure as well as corrosion damage to the wiring board can occur, thereby causing the electric junction box not to function properly.
To solve the afore-mentioned problems, there has been proposed an electric junction box comprising a body having a groove formed on the inner surface of the bottom wall (i.e., bottom face), and an outlet communicating with one end of the groove. This electric junction box is, for example, disclosed in Japanese Publication of Un-examined Patent Application No. 2003-348732. The groove is formed along the longitudinal direction of the connector block and is also inclined downward toward the outlet. When water leaks into the case via the hole, the groove can efficiently take up water and guide it to the outlet, thus allowing the water to be drained away from the case.
Further, there have been proposed an electric junction box having a groove formed along the width direction of the connector block and inclined downward toward the outlet, as disclosed in two Japanese Publications of Un-examined Patent Applications No. 2004-328842 and No. 2000-102138, as well as, an electric junction box having a groove formed along both longitudinal and width direction of the connector block and inclined downward toward the outlet, as disclosed in Japanese Publication of Un-examined Patent Application No. 2002-152943.
Meanwhile, in the case of using the afore-mentioned electric junction boxes as disclosed in Japanese Publication of Un-examined Patent Applications No. 2003-348732 and No. 2002-152943, water that leaks into the case and arrives at the bottom face of the connector block is inclined to form a plurality of discrete droplets without flowing along the groove. In this case, the droplets remains at the bottom face of the connector block so as not to be well drained via the outlet. Furthermore, the water that still remains within the case can adversely affect the wiring board received within the case and the electric components mounted on the wiring board. For example, due to the water, short-circuit failure as well as corrosion damage to the wiring board can occur, thereby causing the electric junction box not to function properly.
Therefore, the object of the present invention can be attained by an electric junction box that is configured to effectively take up the remaining water therein and drain it therefrom.